One-component polyurethane or polyurea compositions

ABSTRACT

The present invention is directed to a one-component polyurethane or polyurea composition which is based on 
     a) a liquid blocked polyisocyanate wherein the isocyanate groups have been blocked with a phenolic blocking agent and 
     b) a solid polyamine which is insoluble in and dispersed throughout the liquid blocked polyisocyanate, 
     wherein the composition may be cured at elevated temperature and also at ambient temperature if the solid polyamine contains nonaromatically bound amino groups. 
     The present invention is also directed to a process for the preparation of a high molecular weight polymer by heating the one-component composition at elevated temperature or by adding a polar solvent to the coating composition and allowing the composition to cure at ambient temperatures, provided that the solid polyamine contains nonaromatically bound amino groups.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to one-component polyurethane orpolyurea compositions based on solid polyamines dispersed in liquidblocked polyisocyanates which may be cured at elevated temperature orunder certain circumstances at ambient temperature.

2. Description of the Prior Art

One component polyurethane compositions are known. For example, U.S.Pat. No. 3,488,302 is directed to solid isocyanatereactive compounds,preferably polyols such as pentaerythritol, dispersed in a liquidisocyanate-terminated prepolymer at an equivalent ratio ofisocyanate-reactive groups to isocyanate groups of about 2:1 to 100:1,preferably about 5:1 to 30:1. U.S. Pat. Nos. 4,390,678 and 4,412,033 aredirected to solid polyols such as pentaerythritol dispersed in liquidisocyanate-terminated prepolymers based on aromatic and aliphaticpolyisocyanates, respectively. In all of these patents it is disclosedthat the one-component polyurethane compositions are cured by heatingthe compositions above the melting point of the dispersed polyol.

U.S. Pat. No. 4,483,974 is also directed to a one-component polyurethanecomposition; however, in this case solid polyisocyanates are dispersedin a liquid isocyanatereactive compound. The solid polyisocyanates havea polyurea surface skin, prepared by reacting the polyisocyanates withcompounds such as polyamines, in order to retard their reaction with theliquid isocyanate-reactive compound. This patent discloses curing theone-component compositions by heating the compositions above the meltingpoint of the solid polyisocyanate. It is also disclosed (column 3, lines35-44; column 4, lines 56-61; column 24, line 61 through column 25, line19; and Example 23) that the compositions may be cured by adding a polarsolvent to dissolve the solid polyisocyanate. Suitable polar solventsare those which are inert to isocyanate groups.

In all of the previously described one-component polyurethanecompositions, free isocyanate groups remain in the compositions.Accordingly, special handling precautions must be followed when workingwith these compositions. Also, care must be taken to avoid the presenceof moisture since it can react with the free isocyanate groups and limitthe effectiveness of these compositions for their intended use. Thismeans that all additives such as pigments and solvents be dewatered.

One-component compositions based on blocked polyisocyanates and anisocyanate-reactive compound are also known. Because these compositionsdo not contain free isocyanate groups, they do require elevatedtemperatures for curing which precludes their use in certainapplications requiring low temperature curing conditions, e.g., toprotect the substrate.

Accordingly, it is an object of the present invention to provideone-component polyurethane or polyurea compositions which can be curedat elevated temperatures or under certain circumstances at ambienttemperature. It is also an object of the present invention to providecompositions which do not contain free isocyanate groups and, thus, donot require special handling procedures or the extra expense of removingwater from additives.

These objects may be achieved in accordance with the present inventionas described hereinafter.

SUMMARY OF THE INVENTION

The present invention is directed to a one-component polyurethane orpolyurea composition which is based on

a) a liquid blocked polyisocyanate wherein the isocyanate groups havebeen blocked with a phenolic blocking agent and

b) a solid polyamine which is insoluble in and dispersed throughout theliquid blocked polyisocyanate,

wherein the composition may be cured at elevated temperature and also atambient temperature if the solid polyamine contains nonaromaticallybound amino groups.

The present invention is also directed to a process for the preparationof a high molecular weight polymer by heating the one-componentcomposition at elevated temperature or by adding a polar solvent to thecoating composition and allowing the composition to cure at ambienttemperatures, provided that the solid polyamine contains nonaromaticallybound amino groups.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention "polyurethane" is defined as apolyisocyanate polyaddition product which contains both urethane andurea groups and "polyurea" is defined as a polyisocyanate polyadditionproduct which contains urea groups.

Polyisocyanates which are suitable for use in accordance with thepresent invention are those wherein the isocyanate groups have beenblocked with a phenolic blocking agent. The isocyanate groups may havearomatically-, aliphatically-, cycloaliphatically- oraraliphatically-bound isocyanate groups. The polyisocyanates prior tothe blocking reaction have an isocyanate content of about 1 to 30,preferably about 2 to 25 weight percent, based on the polyisocyanate,and contain an average of about 2 to 6, preferably about 2 to 4isocyanate groups per molecule.

The polyisocyanates which are suitable for use in preparing thepolyisocyanate component may be monomeric polyisocyanates,polyisocyanate adducts or isocyanate-terminated prepolymers. Thepolyisocyanate adducts are generally prepared from monomericpolyisocyanates, preferably monomeric diisocyanates and contain biuret,allophanate, urea, urethane, carbodiimide or uretdione groups orisocyanurate rings. Suitable polyisocyanates which may be used as themonomeric polyisocyanates or for preparing the polyisocyanate adductsinclude organic diisocyanates represented by the general formula

    R(NCO).sub.2

in which R represents an organic group obtainable by removal of theisocyanate groups from an organic diisocyanate having a molecular weightof from about 112 to 1,000, and preferably from about 140 to 400.Preferred diisocyanates are those represented by the general formulaindicated above in which R represents a divalent aliphatic hydrocarbongroup having from 4 to 18 carbon atoms, a divalent cycloaliphatichydrocarbon group having from 5 to 15 carbon atoms, a divalentaraliphatic hydrocarbon group having from 7 to 15 carbon atoms or adivalent aromatic hydrocarbon group having 6-15 carbon atoms. Examplesof the organic diisocyanates which are particularly suitable for theprocess include 1,4-tetramethylene diisocyanate, 1,6-hexamethylenediisocyanate, 2,2,4-trimethyl-1,6-hexamethylene diisocyanate,1,12-dodecamethylene diisocyanate, cyclohexane-1,3- and-1,4-diisocyanate, 1-isocyanato-2-isocyanatomethylcyclopentane,1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane (isophoronediisocyanate or IPDI), bis-(4-isocycanatocyclohexyl)methane, 1,3- and1,4-bis(isocyanatomethyl)-cyclohexane,bis-(4-isocyanato-3-methyl-cyclohexyl)-methane,α,α,α',α'-tetramethyl-1,3- and/or -1,4-xylylene diisocyanate,1-isocyanato-1-methyl-4(3)-isocyanatomethyl cyclohexane, 2,4- and/or2,6-hexahydrotoluylene diisocyanate, 1,3- and/or 1,4-phenylenediisocyanate, 2,4- and/or 2,6-toluylene diisocyanate, 2,4- and/or4,4,-diphenylmethane diisocyanate and 1,5-diisocyanato naphthalene. Alsosuitable are polyisocyanates such as 4,4',4"-triphenylmethanetriisocyanate and polyphenyl polymethylene polyisocyanates obtained byphosgenating aniline/formaldehyde condensates. Mixtures of diisocyanatesand/or polyisocyanates may, of course, also be used. Preferreddiisocyanates are 1,6-hexamethylene diisocyanate, isophoronediisocyanate, bis-(4-isocyanatocyclohexyl)-methane, 2,4- and/or 2,6-toluylene diisocyanate and 2,4,- and/or 4,4'-diphenylmethanediisocyanate.

Polyisocyanate adducts containing biuret groups may be prepared from thepreviously mentioned diisocyanates according to the processes disclosedin U.S. Pat. Nos. 3,124,605; 3,358,010; 3,644,490; 3,862,973; 3,903,126;3,903,127; 4,051,165; 4,147,714 or 4,220,749 by using co-reactants suchas water, tertiary alcohols, primary and secondary monoamines, andprimary and/or secondary diamines. The preferred diisocyanate to be usedin these processes is 1,6-diisocyanatohexane.

Polyisocyanate adducts containing allophanate groups may be prepared byreacting the previously mentioned diisocyanates according to theprocesses disclosed in U.S. Pat. Nos. 3,769,318 and 4,160,080, BritishPatent 994,890 and German Offenlegungsschrift 2,040,645.

Polyisocyanate adducts containing isocyanurate groups may be prepared bytrimerizing the previously mentioned diisocyanates in accordance withthe processes disclosed in U.S. Pat. Nos. 3,487,080; 3,919,218;4,040,992; 4,288,586; and 4,324,879; German Auslegeschrift 1,150,080;German Offenlegungsschrift 2,325,826; and British Patent 1,465,812. Thepreferred diisocyanates to be used are 2,4-diisocyanatotoluene,2,6-diisocyanatotoluene, mixtures of these isomers,1,6-diisocyanatohexane, isophorone diisocyanate and mixtures of theselatter two diisocyanates.

Polyisocyanate adducts containing urea or preferably urethane groups andbased on the reaction product of the previously mentioned diisocyanatesand compounds having a molecular weight of less than 400 and containing2 or more isocyanate-reactive hydrogens may be prepared according to theprocess disclosed in U.S. Pat. No. 3,183,112. When preparingpolyisocyanate adducts using a large excess of diisocyanate, the averageisocyanate functionality may be determined from the functionality of thecompounds containing isocyanate-reactive hydrogens. For example,theoretically when an excess of a diisocyanate is reacted with a diol, apolyisocyanate with a functionality of approximately 2 will be produced,while a triol co-reactant will result in a polyisocyanate functionalityof at least 3. By using mixtures of compounds containingisocyanate-reactive hydrogens, various functionalities can be obtained.The preferred isocyanate-reactive hydrogens are provided by hydroxylgroups, although other groups such as amino groups are not excluded.Suitable compounds containing isocyanate-reactive hydrogens aredisclosed in U.S. Pat. No. 3,183,112, incorporated herein by reference,and include ethylene glycol, 1,2- and 1,3-propylene glycol, 1,3- and1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol,diethylene glycol, 2-methyl-1,3-propylene glycol, 2,2-dimethyl-1,3-propylene glycol, the various isomeric bis-hydroxymethylcyclohexanes, 2,2,4-trimethyl-1,3-pentanediol, glycerine, trimethylolpropane, ethylene diamine, diethylene triamine, triethylene tetraamine,1,6 -hexanediamine, piperazine, 2,5-dimethyl piperazine,1-amino-3-aminomethyl3,5,5- trimethylcyclohexane,bis(4-aminocyclohexyl)methane, bis(4-amino-3-methylcyclohexyl)methane,1,4-cyclohexanediamine, 1,2-propanediamine, hydrazine, aminoacidhydrazides, hydrazides of semicarbazido carboxylic acids, bis-hydrazidesand bis-semicarbazides. 1,3- and 1,4-butanediol,2,2,4-trimethyl-1,3-pentanediol, trimethylol propane and mixturesthereof are particularly preferred. It is also possible to use any ofthe previously described polyisocyanate adducts for the furtherpreparation of polyisocyanate adducts containing urethane or ureagroups. Preferred diisocyanates are 2,4-diisocyanatotoluene,2,6-diisocyanatotoluene, 1,6-diisocyanatohexane, isophorone diisocyanateand mixtures of these diisocyanates.

In addition to using the previously described monomeric polyisocyanatesor polyisocyanate adducts as the polyisocyanate component of the presentinvention, it is also suitable to prepare the polyisocyanate componentfrom isocyanate-terminated prepolymers. These prepolymers are formed byreacting an excess of the previously described polyisocyanates,preferably monomeric diisocyanates, with high molecular weightisocyanate-reactive compounds and optionally low molecular weightisocyanate-reactive compounds. Prepolymers prepared exclusively frompolyisocyanates and low molecular weight isocyanate-reactive compoundsare referred to as polyisocyanate adducts containing urea and/orurethane groups and have previously been discussed. A sufficient excessof the polyisocyanate should be used to ensure that the prepolymers areterminated with isocyanate groups. The high molecular weight compoundsto be used with the previously described polyisocyanates for preparingthe isocyanateo terminated prepolymers are selected from the knowncompounds containing isocyanate-reactive groups, preferably hydroxylgroups, which are at least difunctional in the sense of theisocyanate-addition reaction. These compounds generally have an averagefunctionality of about 2 to 8, preferably 2 to 4. The compoundscontaining at least two isocyanate-reactive hydrogen atoms generallyhave a molecular weight (M_(n), as determined by end group analysis) of400 to about 10,000, preferably 400 to about 8,000.

Examples of the high molecular weight compounds are polyester polyols,polyether polyols and amines, polyhydroxy polycarbonates, polyhydroxypolyacetals, polyhydroxy polyacrylates, polyhydroxy polyester amides andpolyhydroxy polythioethers. The preferred high molecular weightisocyanate-reactive compounds for use in the process according to theinvention are the polyhydroxyl polyethers, polyesters, polylactones,polycarbonates, polyester carbonates and especially polyacrylates.

Suitable polyester polyols include reaction products of polyhydric,preferably dihydric alcohols to which trihydric alcohols may be addedand polybasic, preferably dibasic carboxylic acids. Instead of thesepolycarboxylic acids, the corresponding carboxylic acid anhydrides orpolycarboxylic acid esters of lower alcohols or mixtures thereof may beused for preparing the polyesters. The polycarboxylic acids may bealiphatic, cycloaliphatic, aromatic and/or heterocyclic and they may besubstituted, e.g. by halogen atoms, and/or unsaturated. The followingare mentioned as examples: succinic acid; adipic acid; suberic acid;azelaic acid; sebacic acid; phthalic acid; isophthalic acid; trimelliticacid; phthalic acid anhydride; tetrahydrophthalic acid anhydride;hexahydrophthalic acid anhydride; tetrachlorophthalic acid anhydride,endomethylene tetrahydrophthalic acid anhydride; glutaric acidanhydride; maleic acid; maleic acid anhydride; fumaric acid; dimeric andtrimeric fatty acids such as oleic acid, which may be mixed withmonomeric fatty acids; dimethyl terephthalates and bis-glycolterephthalate. Suitable polyhydric alcohols include, e.g. ethyleneglycol; propylene glycol-(1,2) and -(1,3); butylene glycol-(1,4) and-(1,3); hexanediol-(1,6); octanediol-(1,8); neopentyl glycol;cyclohexanedimethanol (1,4-bis-hydroxymethylcyclohexane);2-methyl-1,3-propanediol; 2,2,4-trimethyl-],3-pentanediol; triethyleneglycol; tetraethylene glycol; polyethylene glycol; dipropylene glycol;polypropylene glycol; dibutylene glycol and polybutylene glycol,glycerine and trimethlyolpropane. The polyesters may also contain aportion of carboxyl end groups. Polyesters of lactones, e.g.ε-caprolactone or hydroxycarboxylic acids, e.g. δ-hydroxycaproic acid,may also be used.

Polycarbonates containing hydroxy groups include those known per se suchas the products obtained from the reaction of diols such aspropanediol-(3), butanediol-(1,4) and/or hexanediol-(1,6), diethyleneglycol, triethylene glycol or tetraethylene glycol with phosgene,diarylcarbonates such as diphenylcarbonate or with cyclic carbonatessuch as ethylene or propylene carbonate. Also suitable are polyestercarbonates obtained form the above-mentioned polyesters or polylactoneswith phosgene, diaryl carbonates or cyclic carbonates.

Suitable polyether polyols are obtained in known manner by the reactionof starting compounds which contain reactive hydrogen atoms withalkylene oxides such as ethylene oxide; propylene oxide; butylene oxide;styrene oxide; tetrahydrofuran or epichlorohydrin or with mixtures ofthese alkylene oxides. It is preferred that the polyethers do notcontain more than about 10% by weight of ethylene oxide units. Mostpreferably, polyethers obtained without the addition of ethylene oxideare used. Suitable starting compounds containing reactive hydrogen atomsinclude the polyhydric alcohols set forth for preparing the polyesterpolyols and, in addition, water, methanol, ethanol, 1,2,6-hexane triol,1,2,4-butane triol, trimethylol ethane, pentaerythritol, mannitol,sorbitol, methyl glycoside, sucrose, phenol, isononyl phenol,resorcinol, hydroquinone, 1,1,1- or 1,1,2-tris(hydroxylphenyl)-ethane.

Polyethers which have been obtained by the reaction of startingcompounds containing amine compounds can also be used, but are lesspreferred for use in the present invention. Suitable amine startingcompounds include: ammonia, methyl amine, tetramethylene diamine,ethanolamine, diethanolamine, triethanolamine, ethylene diamine,diethylene triamine, triethylene tetramine, 1,6-hexane diamine,piperazine, 2,5-dimethyl piperazine,1-amino-3-aminomethyl-3,3,5-trimethyl cyclohexane,bis-(4-aminocyclohexyl)-methane,bis-(4-amino-3-methylcyclohexyl)-methane, 1,4-cyclohexane diamine,1,2-propane diamine, hydrazine, aminoacid hydrazides, hydrazides ofsemicarbazido carboxylic acids, bis-hydrazides, bis-semicarbazides,aniline, phenylene diamine, 2,4- and 2,6-toluylene diamine,polyphenylene polymethylene polyamines of the kind obtained by theaniline/formaldehyde condensation reaction and mixtures thereof.Resinous materials such as phenol and cresol resins may be used as thestarting materials.

Polyethers modified by vinyl polymers are also suitable for the processaccording to the invention. Products of this kind may be obtained bypolymerizing, e.g. styrene and acrylonitrile in the presence ofpolyethers (U.S. Pat. Nos. 3,383,351; 3,304,273; 3,523,095; 3,110,695and German Patent No. 1,152,536). Also suitable as polyethers are aminopolyethers wherein at least a portion of the hydroxyl groups of thepreviously described polyethers are converted to amino groups.

The preferred starting compounds for the polyethers are those compoundswhich exclusively contain hydroxyl groups, while compounds containingtertiary amine groups are less preferred and compounds containingisocyanate-reactive --NH groups are much less preferred.

Among the polythioethers which should be particularly mentioned are thecondensation products obtained from thiodiglycol on its own and/or withother glycols, dicarboxylic acids, formaldehyde, aminocarboxylic acidsor amino alcohols. The products obtained are either polythio-mixedethers, polythioether esters or polythioether ester amides, depending onthe co-components.

Suitable polyacetals include the compounds which can be prepared fromaldehydes, e.g. formaldehyde, and glycols such as diethylene glycol,triethylene glycol, ethoxylated 4,4 -dihydroxy-diphenyldimethylmethane,and hexanediol-(1,6). Polyacetals suitable for the purpose of theinvention may also be prepared by the polymerization of cyclic acetals.

Suitable polyhydroxy polyester amides and polyamines are, for example,the predominantly linear condensates obtained from polybasic saturatedand unsaturated carboxylic acids or their anhydrides and polyvalentsaturated or unsaturated aminoalcohols, diamines, polyamines andmixtures thereof.

Suitable monomers for producing hydroxy-functional polyacrylates includeacrylic acid, methacrylic acid, crotonic acid, maleic anhydride,2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropylacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate,3-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate,2-isocyanatoethyl acrylate and 2-isocyanatoethyl methacrylate.

In addition to the high molecular weight compounds, theisocyanate-terminated prepolymers may also optionally be prepared fromlow molecular weight isocyanate-reactive compounds having an averagemolecular weight of up to 400. The low molecular weightisocyanate-reactive compounds should have an average functionality ofabout 2 to 8, preferably from about 2 to 6 and most preferably fromabout 2 to 4, and may also contain ether, thioether, ester, urethaneand/or urea bonds.

Examples of low molecular weight compounds include the polyamines anddiols or triols used as chain lengthening agents or cross-linking agentsin polyurethane chemistry such as those listed as suitable for preparingthe polyisocyanate adducts containing urethane or urea groups and thepolyester and polyether polyols. Additional examples include those setforth in U.S. Pat. Nos. 4,439,593 and 4,518,522, both of which areherein incorporated by reference in their entirety.

A solvent or solvent mixture may be used during the production of thepolyisocyanate adducts or isocyanate-terminated prepolymers althoughsolvents are not necessary. When a solvent is employed, e.g., to promotethorough mixing of the compounds used for preparing theisocyanate-terminated prepolymer, the solvent or solvent mixture issubsequently distilled off, preferably under vacuum, leaving aready-to-use, liquid polyisocyanate component in solvent-free form.

Suitable solvents include the known polyurethane solvents, for example,toluene, xylene, butyl acetate, ethylacetate, ethylene glycol monoethylether acetate (EGA), ethylene glycol monomethyl ether acetate, ethyleneglycol monobutyl ether acetate, diethylene glycol monoethyl etheracetate, diethylene glycol monomethyl ether acetate, diethylene glycolmonobutyl ether acetate, propylene glycol monomethyl ether acetate,methyl ethyl ketone or methyl isobutyl ketone, hydrocarbon solvents suchas hexane and heptane, aromatic solvents and also mixtures of the abovesolvents.

Prior to their use in accordance with the present invention, theisocyanate groups of the polyisocyanate component are blocked with aphenolic blocking agent. Examples of suitable blocking agents includephenol or alkylated phenols such as nonylphenol, the cresols, thetrimethyl phenols and the tert.-butyl phenols. The reaction between theisocyanate groups and the blocking agent is conducted at a temperatureof about 50° to 120° C., preferably about 70° to 100° C. The reactionmay be conducted in the presence of a solvent although the presence of asolvent is not necessary. Suitable solvents include those previously setforth for preparing the polyisocyanate adducts or isocyanate-terminatedprepolymers.

Suitable polyamines for use in accordance with the present invention arethose which remain stable in the presence of the polyisocyanatecomponent for at least one week, preferably for at least two weeks, whenstored at ambient temperature. In order to satisfy this requirementsuitable polyamines are solid at temperatures above 30° C., preferablyabove 60° C. The polyamines have a molecular weight (M_(n), asdetermined by end group analysis) of about 100 to 10,000, preferablyabout 100 to 6000 and most preferably about 100 to 400, and have anaverage functionality of about 2 to 8, preferably about 2 to 4.

Examples of suitable polyamines include the trans/trans isomer of4,4'-diaminodicyclohexyl methane, 4,4'-diaminodiphenyl methane and2,4-diamino-toluylene.

In order to prepare the one-component compositions according to thepresent invention, the solid polyamine component is dispersed into theliquid polyisocyanate component. The amounts of these components areselected to provide an equivalent ratio of isocyanate groups to aminegroups of about 4:1 to 0.5:1.0, preferably about 1.8:1.0 to 0.8:1.0.

In accordance with the present invention it is possible to replace up to75% by weight, preferably up to 50% by weight of the liquid blockedpolyisocyanate with an epoxy resin in order to improve the hardness oradhesion to substrates of the resulting polyurethane or polyurea.Generally, in order to obtain improved hardness or adhesion, it isnecessary to replace at least 5% by weight, preferably at least 10% byweight of the liquid blocked polyisocyanate. In determining the amountof solid polyamine internal salt to be dispersed into the mixture ofliquid blocked polyisocyanate and epoxy resin, an epoxide group isconsidered to be the same as one isocyanate group such that the ratio ofisocyanate and epoxide groups to amino groups should conform to theabove ratios.

Suitable epoxy resins have an average molecular weight (M_(n), asdetermined by end group analysis) of 500 to 20,000, preferably about 500to 5000. The epoxy resins may be prepared from a dihydric phenol and adiglycidyl ether of a dihydric phenol. Both the dihydric phenol and thediglycidyl ether of a dihydric phenol may also contain othersubstituents such as alkyl, aryl, sulfido, sulfonyl, halo, etc.

Examples of suitable phenols include 2,2-bis(4-hydroxyphenyl)-propane,2,2-bis(3-bromo-4-hydroxyphenyl)propane,2,2-bis(3-chloro-4-hydroxyphenyl)-propane, bis(4-hydroxyphenyl)methane,bis(4-hydroxyphenyl)-sulfone, bis(4-hydroxyphenyl)sulfide, resorcinol,hydroquinone, and the like. The preferred dihydric phenols are2,2-bis(4-hydroxy-phenyl)-propane (bisphenol A) andbis(4-hydroxyphenyl)methane for reasons of cost and availability.

The diglycidyl ether derivatives are prepared by the reaction of adihydric phenol with a halogen-containing epoxide or dihalohydrin in thepresence of an alkaline medium. By varying the ratios of the dihydricphenol and epichlorohydrin reactants, different molecular weightproducts can be obtained as described in U.S. Pat. Nos. 2,582,985;2,615,007 and 2,633,458.

For purposes of the present invention, optionally at least a portion ofthe diglycidyl ether of a dihydric phenol component can be replaced witha diglycidyl ether of a hydrogenated dihydric phenol derivative. Forexample, the diglycidyl ether of dihydric phenol can have up toessentially 100 percent of its weight substituted by a diglycidyl ethersuch as 2,2-bis(4-hydroxycyclohexyl)propane orbis(4-hydroxycyclohexyl)methane.

The compositions according to the present invention may be cured atambient temperature by the addition of a polar solvent provided that thesolid polyamine contains nonaromatically bound amino groups such asaliphatically or cycloaliphatically bound amino groups. Suitablesolvents are those which contain oxygen or nitrogen atoms and may eitherbe inert to isocyanate groups or reactive with isocyanate groups.Examples of solvents which are inert to isocyanate groups include butylacetate, ethylacetate, ethylene glycol monoethyl ether acetate, ethyleneglycol monomethyl ether acetate, ethylene glycol monobutyl etheracetate, diethylene glycol monoethyl ether acetate, diethylene glycolmonomethyl ether acetate, diethylene glycol monobutyl ether acetate,propylene glycol monomethyl ether acetate, methyl ethyl ketone, methylisobutyl ketone, propylene carbonate, dioxane, dimethyl formamide,N-methyl pyrrolidinone and mixtures of the these solvents. N-methylpyrrolidinone is especially preferred.

Examples of solvents which are reactive with isocyanate groups includehydroxyl group-containing solvents, preferably solvents having 1 to 8carbon atoms such as methanol, ethanol, n-propanol, isopropanol,n-butanol, isobutanol, tert. butanol, n-hexanol, cyclohexanol and2-ethylhexanol. Isopropanol is especially preferred. Mixtures of waterand polar solvents, especially N-methyl pyrrolidinone, are considered tobe reactive solvents in accordance with the present invention.

The preferred amount of the polar solvent to be added in order to curethe compositions of the present invention is about 5 to 100 weightpercent, more preferably about 10 to 80 weight percent, based on theweight of the liquid polyisocyanate component and the solid polyamine.Greater amounts of solvent may be used, e.g., to reduce the viscosity ofthe composition to an appropriate level for its intended application.However, larger amounts of solvent than are necessary to cure thecompositions are not preferred for environmental reasons.

The compositions according to the present invention may also be cured atelevated temperatures, i.e., at temperatures above the melting point ofthe solid polyamines. Temperatures which are sufficient to unblock thepolyisocyanate may also be used when an extremely rapid cure of thecomposition is desired. Generally, the compositions are cured attemperatures of about 70° to 200° C., preferably about 100 to 140° C.

The one-component compositions of the present invention can be cured toform high quality elastomers, coatings, cellular elastomers and moldingsoptionally having a density distribution characterized by a cellularinner core and a more compact outer skin.

The invention is further illustrated but is not intended to be limitedby the following examples in which all parts and percentages are byweight unless otherwise specified.

EXAMPLE 1 Preparation of an Isocyanate-terminated Prepolymer

Into a 1000 ml three-neck flask equipped with a mechanical stirrer and athermometer was charged 64.8 parts of TDI (which is an 80/20 weightpercent mixture of the 2,4-isomer and 2,6-isomer of toluylenediisocyanate). To the stirred contents of the flask, which wasmaintained at 70° C., were added 468.0 parts of a polyether polyolhaving secondary hydroxyl groups, an OH number of 42 and a functionalityof 2.6 and prepared by alkoxylating a mixture of 74 weight percentglycerine and 24 weight percent propylene glycol with a mixture of 85weight percent propylene oxide and 15 weight percent ethylene oxide.Upon completion of the addition, the temperature of the reaction mixtureincreased slightly due to the exothermic reaction. The contents of theflask were maintained at 70° C. for 2 hours or until the theoreticalisocyanate content was obtained. Thereafter, 105.6 parts of nonyl phenoland 0.08 parts of stannous octoate were added, the temperature wasdecreased to 50° C., and the reaction mixture was maintained at thistemperature for 3 hours or until there was no detectable isocyanatecontent. The blocked prepolymer was then poured from the reaction flaskinto a storage container, purged with nitrogen, sealed and allowed tocool to ambient temperature.

EXAMPLE 2 Preparation of a One Component Composition a) According to thePresent Invention

A one component composition according to the present invention wasprepared by dispersing 7.6 parts of 2,4-toluylene diamine into 200.0parts of the blocked isocyanate-terminated prepolymer of Example 1. Thecomposition was stable for more than one week at room temperature. Afterstorage the composition was cured at 115° C. for three hours to form acured coating.

b) Comparison

In a similar manner a one component coating composition was prepared bymixing 3.9 parts of diethylene triamine, a liquid polyamine, with 200.0of the blocked isocyanate-terminated prepolymer of Example 1. Thecomposition gelled in one hour at room temperature demonstrating thenecessity of using solid polyamines in accordance with the presentinvention.

EXAMPLE 3 Preparation of a One Component Composition

When a composition based on 200 parts of the blockedisocyanate-terminated prepolymer of Example 1 and 10 parts of thetrans/trans isomer of 4,4'-diaminodicylohexyl methane is blended with anequal amount of a solvent such as isopropanol or a mixture ofN-methylpyrrolidone and water, the composition solidifies within a fewhours.

Although the invention has been described in detail in the foregoing forthe purpose of illustration, it is to be understood that such detail issolely for that purpose and that variations can be made therein by thoseskilled in the art without departing from the spirit and scope of theinvention except as it may be limited by the claims.

What is claimed is:
 1. A one-component polyurethane or polyureacomposition which may be cured at elevated temperature and comprisesa) aliquid blocked polyisocyanate wherein the isocyanate groups have beenblocked with a phenolic blocking agent and b) a solid polyamine which isinsoluble in and dispersed throughout the liquid blocked polyisocyanate.2. The composition of claim 1 wherein said liquid blocked polyisocyanatecomprises a blocked isocyanate-terminated prepolymer.
 3. The compositionof claim 1 wherein said phenolic blocking agent comprises nonyl phenol.4. The composition of claim 1 wherein said solid polyamine comprises2,4-toluylene diamine.
 5. The composition of claim 1 wherein 5 to 75% byweight of the liquid blocked polyisocyanate is replaced by an epoxyresin.
 6. A one-component polyurethane or polyurea composition which maybe cured at either ambient or elevated temperature and comprisesa) aliquid blocked polyisocyanate wherein the isocyanate groups have beenblocked with a phenolic blocking agent and b) a solid polyamine whichcontains nonaromatically bound amino groups and is insoluble in anddispersed throughout the liquid blocked polyisocyanate.
 7. Thecomposition of claim 6 wherein said liquid blocked polyisocyanatecomprises a blocked isocyanate-terminated prepolymer.
 8. The compositionof claim 6 wherein said phenolic blocking agent comprises nonyl phenol.9. The composition of claim 6 wherein said solid polyamine comprises2,4-toluylene diamine the trans/trans isomer of 4,4'diaminodicylohexylmethane.
 10. The composition of claim 6 wherein 5 to 75% by weight ofthe liquid blocked polyisocyanate is replaced by an epoxy resin.
 11. Aprocess for the preparation of a polyurethane or polyurea whichcomprises heating a composition comprisinga) a liquid blockedpolyisocyanate wherein the isocyanate groups have been blocked with aphenolic blocking agent and b) a solid polyamine which is insoluble inand dispersed throughout the liquid blocked polyisocyanate, to atemperature above the melting point of said solid polyamine.
 12. Aprocess for the preparation of a polyurethane or polyurea whichcomprises adding a polar solvent to a composition comprisinga) a liquidblocked polyisocyanate wherein the isocyanate groups have been blockedwith a phenolic blocking agent and b) a solid polyamine which containsnonaromatically bound amino groups and is insoluble in and dispersedthroughout the liquid blocked polyisocyanate.